If the DNS client screening feature prevents your multi-homed server from accessing a DNS server that is otherwise available, you may wish to disable the feature. The DNS client service does not access the DNS servers that appear to be unreachable from the interface on which they are configured. The DNS servers are marked unreachable for the server, even though they may be available to the other network adapter on the same server.
To disable the DNS client screening feature on Windows Server 2003:
1. Open a CMD.EXE window.
2. Type the following commands, pressing Enter after each line:
REG ADD HKLM\SYSTEM\CurrentControlSet\Services\Dnscache\Parameters /V ScreenUnreachableServers /T REG_DWORD /F /D 0
net stop Dnscache
net start Dnscache